File size: 10,317 Bytes
d5b7741
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
import OAI.Combinatorics.ContingencyTables.Transport.GraphCompletionCounts

namespace OAI

/-!
# The companion's actual small/free profiles and tree intervals

Residual margins subtract the two separate small views and the fixed
free values. The integral graph completion satisfies every nonroot line.
The maximum-forest cut bound then supplies, rather than assumes, the
physical tree interval used by the signature/count marginal.
-/

namespace ContingencyTables.ForestPhysicalCompletion

open scoped BigOperators Classical
open SimpleGraph
open ForestCapacity GraphIntegralCompletion GraphCompletionCounts

variable {I J : Type*} [Fintype I] [Fintype J]

noncomputable def fixedRow (small : I → J → Bool) (T : SimpleGraph (I⊕J))
    (x free : I → J → ℤ) (i : I) (j : J) : ℤ :=
  if small i j then x i j else if T.Adj (.inl i) (.inr j) then 0 else free i j

noncomputable def fixedColumn (small : I → J → Bool) (T : SimpleGraph (I⊕J))
    (q free : I → J → ℤ) (i : I) (j : J) : ℤ :=
  if small i j then q i j else if T.Adj (.inl i) (.inr j) then 0 else free i j

noncomputable def rowResidual (small : I → J → Bool) (T : SimpleGraph (I⊕J))
    (r : I → ℤ) (x free : I → J → ℤ) (i : I) : ℤ :=
  r i-∑ j, fixedRow small T x free i j

noncomputable def columnResidual (small : I → J → Bool) (T : SimpleGraph (I⊕J))
    (c : J → ℤ) (q free : I → J → ℤ) (j : J) : ℤ :=
  c j-∑ i, fixedColumn small T q free i j

noncomputable def solved (small : I → J → Bool) (T : SimpleGraph (I⊕J))
    (r : I → ℤ) (c : J → ℤ) (x q free : I → J → ℤ) : I → J → ℤ :=
  tableCompletion T (rowResidual small T r x free) (columnResidual small T c q free)

noncomputable def completed (small : I → J → Bool) (T : SimpleGraph (I⊕J))
    (r : I → ℤ) (c : J → ℤ) (x q free : I → J → ℤ) (i : I) (j : J) : ℤ :=
  if T.Adj (.inl i) (.inr j) then solved small T r c x q free i j else free i j

lemma row_pointwise (small : I → J → Bool) (T : SimpleGraph (I⊕J))
    (hTG : T≤cellGraph small) (r : I → ℤ) (c : J → ℤ) (x q free : I → J → ℤ)
    (i : I) (j : J) :
    (if small i j then x i j else completed small T r c x q free i j)=
      solved small T r c x q free i j+fixedRow small T x free i j := by
  by_cases ht : T.Adj (.inl i) (.inr j)
  · have hs : small i j=false := hTG ht
    simp only [hs,Bool.false_eq_true,ite_false,completed,ht,ite_true,fixedRow,add_zero]
  · have hz : solved small T r c x q free i j=0 := tableCompletion_supported T _ _ i j ht
    simp only [completed,ht,ite_false,hz,zero_add,fixedRow]

lemma column_pointwise (small : I → J → Bool) (T : SimpleGraph (I⊕J))
    (hTG : T≤cellGraph small) (r : I → ℤ) (c : J → ℤ) (x q free : I → J → ℤ)
    (i : I) (j : J) :
    (if small i j then q i j else completed small T r c x q free i j)=
      solved small T r c x q free i j+fixedColumn small T q free i j := by
  by_cases ht : T.Adj (.inl i) (.inr j)
  · have hs : small i j=false := hTG ht
    simp only [hs,Bool.false_eq_true,ite_false,completed,ht,ite_true,fixedColumn,add_zero]
  · have hz : solved small T r c x q free i j=0 := tableCompletion_supported T _ _ i j ht
    simp only [completed,ht,ite_false,hz,zero_add,fixedColumn]

lemma row_completed_sum (small : I → J → Bool) (T : SimpleGraph (I⊕J))
    (hTG : T≤cellGraph small) (r : I → ℤ) (c : J → ℤ) (x q free : I → J → ℤ)
    (i : I) (hi : Sum.inl i≠componentRoot T (.inl i)) :
    (∑ j, if small i j then x i j else completed small T r c x q free i j)=r i := by
  simp_rw [row_pointwise small T hTG r c x q free]
  rw [Finset.sum_add_distrib,show (∑ j, solved small T r c x q free i j)=
    rowResidual small T r x free i from tableCompletion_row small T hTG _ _ i hi]
  exact sub_add_cancel _ _

lemma column_completed_sum (small : I → J → Bool) (T : SimpleGraph (I⊕J))
    (hTG : T≤cellGraph small) (r : I → ℤ) (c : J → ℤ) (x q free : I → J → ℤ)
    (j : J) (hj : Sum.inr j≠componentRoot T (.inr j)) :
    (∑ i, if small i j then q i j else completed small T r c x q free i j)=c j := by
  simp_rw [column_pointwise small T hTG r c x q free]
  rw [Finset.sum_add_distrib,show (∑ i, solved small T r c x q free i j)=
    columnResidual small T c q free j from tableCompletion_column small T hTG _ _ j hj]
  exact sub_add_cancel _ _

omit [Fintype I] [Fintype J] in
lemma nonroot_of_root_component (T : SimpleGraph (I⊕J)) (u v : I⊕J)
    (h : T.Reachable (componentRoot T u) v) (hv : v≠componentRoot T u) :
    v≠componentRoot T v := by
  have he : componentRoot T v=componentRoot T u := by
    rw [← componentRoot_constant T h,componentRoot_idempotent]
  simpa only [he] using hv

/-- The completion interval holds for the literal residual
margin equations, including every box-valid unbalanced small profile. -/
theorem solved_in_intervals (small : I → J → Bool) (b : I → J → ℕ)
    (T : SimpleGraph (I⊕J)) (hTG : T≤cellGraph small) (hT : T.IsAcyclic)
    (hmax : ∀ F : SimpleGraph (I⊕J), F≤cellGraph small → F.IsAcyclic →
      MaximumForest.weight F (capacity b)≤MaximumForest.weight T (capacity b))
    (r : I → ℤ) (c : J → ℤ) (x q free X : I → J → ℤ) (d W : ℕ)
    (hd : 1≤d) (hcard : Fintype.card I*Fintype.card J≤d)
    (hlarge : ∀ i j, small i j=false → W≤b i j ∧ 1≤b i j)
    (hsmall : ∀ i j, small i j=true → b i j<W ∧
      (0≤x i j ∧ x i j≤b i j) ∧ (0≤q i j ∧ q i j≤b i j))
    (hfree : ∀ i j, small i j=false → ¬T.Adj (.inl i) (.inr j) →
      0≤free i j ∧ free i j≤b i j)
    (hX : ∀ i j, 0≤X i j ∧ X i j≤b i j)
    (hXr : ∀ i, (∑ j, X i j)=r i) (hXc : ∀ j, (∑ i, X i j)=c j) :
    ∀ i j, T.Adj (.inl i) (.inr j) →
      -((10*d*b i j:ℕ):ℤ) ≤ solved small T r c x q free i j ∧
        solved small T r c x q free i j≤(10*d*b i j:ℕ) := by
  intro i₀ j₀ ht
  let root := componentRoot T (.inl i₀)
  have hb := completion_interval small b T hTG hT hmax i₀ j₀ ht root
    (componentRoot_reachable T (.inl i₀)).symm
    (fun i j => (x i j:ℝ)) (fun i j => (q i j:ℝ))
    (fun i j => (completed small T r c x q free i j:ℝ)) (fun i j => (X i j:ℝ))
    (d:ℝ) W (by exact_mod_cast hd) (by exact_mod_cast hcard) hlarge
    (by
      intro i j hs
      exact ⟨(hsmall i j hs).1,by exact_mod_cast (hsmall i j hs).2.1,
        by exact_mod_cast (hsmall i j hs).2.2⟩)
    (by intro i j; exact_mod_cast hX i j)
    (by
      intro i j hs htree
      have hn : ¬T.Adj (.inl i) (.inr j) := by
        simpa only [treeCell,decide_eq_false_iff_not] using htree
      simp only [completed,hn,ite_false]
      have hf := hfree i j hs hn
      constructor
      · exact_mod_cast hf.1
      · have hcast : (free i j:ℝ)≤(b i j:ℝ) := by exact_mod_cast hf.2
        linarith)
    (by
      intro i hcomp hi
      have hrow := row_completed_sum small T hTG r c x q free i
        (nonroot_of_root_component T (.inl i₀) (.inl i) hcomp hi)
      have hrowR : (∑ j, if small i j then (x i j:ℝ) else
          (completed small T r c x q free i j:ℝ))=(r i:ℝ) := by exact_mod_cast hrow
      have hXR : (∑ j, (X i j:ℝ))=(r i:ℝ) := by exact_mod_cast hXr i
      unfold ForestCut.rowDifference
      calc
        _=(∑ j, if small i j then (x i j:ℝ) else
          (completed small T r c x q free i j:ℝ))-(∑ j, (X i j:ℝ)) := by
            rw [← Finset.sum_sub_distrib]
            apply Finset.sum_congr rfl
            intro j _
            split_ifs <;> rfl
        _=0 := by rw [hrowR,hXR,sub_self])
    (by
      intro j hcomp hj
      have hcol := column_completed_sum small T hTG r c x q free j
        (nonroot_of_root_component T (.inl i₀) (.inr j) hcomp hj)
      have hcolR : (∑ i, if small i j then (q i j:ℝ) else
          (completed small T r c x q free i j:ℝ))=(c j:ℝ) := by exact_mod_cast hcol
      have hXC : (∑ i, (X i j:ℝ))=(c j:ℝ) := by exact_mod_cast hXc j
      unfold ForestCut.columnDifference
      calc
        _=(∑ i, if small i j then (q i j:ℝ) else
          (completed small T r c x q free i j:ℝ))-(∑ i, (X i j:ℝ)) := by
            rw [← Finset.sum_sub_distrib]
            apply Finset.sum_congr rfl
            intro i _
            split_ifs <;> rfl
        _=0 := by rw [hcolR,hXC,sub_self])
  simp only [completed,ht,ite_true] at hb
  constructor
  · have hlow : (-10:ℤ)*(d:ℤ)*(b i₀ j₀:ℤ) ≤ solved small T r c x q free i₀ j₀ := by
      exact_mod_cast hb.1
    convert hlow using 1
    push_cast
    ring
  · exact_mod_cast hb.2

/-- For the literal small/free residual margins, the equality-limit
sum over the prescribed tree intervals retains exactly one term, with
precisely the weight of the source's solved tree values. -/
theorem tree_indicator_sum (small : I → J → Bool) (b : I → J → ℕ)
    (T : SimpleGraph (I⊕J)) (hTG : T≤cellGraph small) (hT : T.IsAcyclic)
    (hmax : ∀ F : SimpleGraph (I⊕J), F≤cellGraph small → F.IsAcyclic →
      MaximumForest.weight F (capacity b)≤MaximumForest.weight T (capacity b))
    (r : I → ℤ) (c : J → ℤ) (x q free X : I → J → ℤ) (d W : ℕ)
    (hd : 1≤d) (hcard : Fintype.card I*Fintype.card J≤d)
    (hlarge : ∀ i j, small i j=false → W≤b i j ∧ 1≤b i j)
    (hsmall : ∀ i j, small i j=true → b i j<W ∧
      (0≤x i j ∧ x i j≤b i j) ∧ (0≤q i j ∧ q i j≤b i j))
    (hfree : ∀ i j, small i j=false → ¬T.Adj (.inl i) (.inr j) →
      0≤free i j ∧ free i j≤b i j)
    (hX : ∀ i j, 0≤X i j ∧ X i j≤b i j)
    (hXr : ∀ i, (∑ j, X i j)=r i) (hXc : ∀ j, (∑ i, X i j)=c j)
    (weight : (I → J → ℤ) → ℝ) :
    (∑ a : TreeIndex T d b,
      if NonrootMargins T (rowResidual small T r x free) (columnResidual small T c q free)
        (physical T d b a) then weight (physical T d b a) else 0)=
      weight (solved small T r c x q free) := by
  exact weighted_completion_sum small T hTG hT (rowResidual small T r x free)
    (columnResidual small T c q free) d b
    (solved_in_intervals small b T hTG hT hmax r c x q free X d W hd hcard hlarge
      hsmall hfree hX hXr hXc) weight

end ContingencyTables.ForestPhysicalCompletion

end OAI